Fluorosulfonylperfluoroalkyl compounds

Abstract

A novel fluorinated copolymer is prepared by copolymerization of a fluorinated olefin with a novel sulfur containing fluorinated vinylether of the formula: ##STR1## wherein k is 0 or 1 and l is an integer of 3 to 5, which is prepared from starting materials which are also novel. Said copolymer is useful for preparation of a fluorinated cation exchange membrane having carboxylic acid groups and/or sulfonic acid groups which can be used advantageously in electrolysis of an aqueous alkali metal halide solution with improved electrolysis performance.

We claim: 
     
       1. A fluorinated carboxylic acid or its derivative represented by the formula:   FSO.sub.2 (CF.sub.2).sub.n Y     wherein Y is --COY 1  or --CN, Y 1  being halogen, hydrogen, --NH 2 , --OM, wherein M is a member selected from the group consisting of hydrogen, a metal and ammonium, or --OR 1 , wherein R 1  is a member selected from the group consisting of C 1  -C 10  alkyl and aryl; and n is an integer of 2 to 4.   
     
     
       2. A fluorinated carboxylic acid or its derivative according to claim 1, wherein n is 2. 
     
     
       3. A fluorinated carboxylic acid or its derivative according to claim 1 or claim 2, wherein Y is --COF. 
     
     
       4. A fluorinated carboxylic acid or its derivative represented by the formula:   FSO.sub.2 CF.sub.2 COF.